pvs-studio: reference becomes invalid when temporary object destroyed

Change-Id: Ibe39738e1a607e3bca273fc03f0f3232024254bc
Reviewed-on: https://gerrit.libreoffice.org/62093
Tested-by: Jenkins
Reviewed-by: Caolán McNamara <caolanm@redhat.com>
Tested-by: Caolán McNamara <caolanm@redhat.com>

canvas/source/directx/dx_canvashelper.cxx

@@ -624,15 +624,15 @@ namespace dxcanvas
 
             // Setup an ImageAttributes with an alpha-modulating
             // color matrix.
-            const rendering::ARGBColor& rARGBColor(
+            rendering::ARGBColor aARGBColor(
                 mpDevice->getDeviceColorSpace()->convertToARGB(renderState.DeviceColor)[0]);
 
             Gdiplus::ImageAttributes aImgAttr;
             tools::setModulateImageAttributes( aImgAttr,
-                                               rARGBColor.Red,
-                                               rARGBColor.Green,
-                                               rARGBColor.Blue,
-                                               rARGBColor.Alpha );
+                                               aARGBColor.Red,
+                                               aARGBColor.Green,
+                                               aARGBColor.Blue,
+                                               aARGBColor.Alpha );
 
             ENSURE_OR_THROW(
                 Gdiplus::Ok == pGraphics->DrawImage( pBitmap.get(),